


Échangé

by Anonymous



Series: Forbidden Kinks [22]
Category: Teen Wolf (TV)
Genre: BDSM, Body Swap, Kinktober 2018, M/M, Memory Alteration, Rape/Non-con Elements, Scat, Technical Cheating But They're Unaware, piss drinking
Language: English
Status: Completed
Published: 2018-10-07
Updated: 2018-10-07
Packaged: 2019-07-27 07:53:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,844
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16214732
Author URL: https://archiveofourown.org/
Summary: Isaac just wanted to have one night with Derek; he'd let Stiles have him for the rest of his life, as long as he had one night.He just wasn't expecting how filthy the "sweet" couple of the pack was behind closed doors; it turns out this one night of his will be less like a dream and more like a nightmare.





	Échangé

**Author's Note:**

> Kinktober 2018, Day 7  
>  ~~Praise Kink~~ | **Body Swap** | ~~Aphrodisiacs~~ | ~~Incest~~

Tying yourself up might seem difficult, but when you’ve recently gone through numerous other difficult things, it’s a cakewalk. Isaac goes through the motions like he’s done it before, when really he’s just been working on his plan for this night for months. He’d started with his legs, using ropes that were thick and didn’t stretch, tying his ankles together first before moving up bit my bit. He added a chain to one of his ankles and connected it to a nearby pipe that was sticking out of the wall, so that he could only move about a foot or so.

He hid the key for that chain underneath a floorboard, as well as the keys for the handcuffs he would be putting on – close enough for him to be able to get at them when he needed to, but hidden enough that nobody else would know they were there.

He shoved a sock – clean, of course, he didn’t want to have the taste of something dirty in his mouth – and taped over it with duct tape, effectively gagging himself. His last touch before he got to the handcuffs was to blindfold himself, tying the bandana he’d brought tightly around the upper half of his face so that he couldn’t see any of his surroundings. Then, bringing his hands behind his back, he looped both his wrists into the handcuffs and locked them in place, just tight enough that his hands couldn’t slip through but loose enough not to pinch his skin anywhere.

Then, he waited for the potion to kick in – he could already feel the tingles starting in his fingertips, and the witch who’d brewed it had told him that was the first sign.

~~

Isaac could never pinpoint the exact time he realized he was in love with Derek Hale; it seemed like one day he wasn’t, and the next he was. Derek had been the one to free him from his life with his father, to make him more powerful than the man who had caused him so much pain, to give him friends and family when he’d thought he’d be all alone forever. And whilst Derek had made many a mistake in the years that followed, he had still been there for Isaac when the bitten werewolf had really needed him.

But he’d realized how he really felt too late, and Stiles got there first. It had been a blow to the gut when Stiles had admitted to Scott that he and Derek were seeing each other, and bigger blows every time he had to see his former Alpha with the human. They weren’t big on PDA, but the intimate touches they gave each other hurt more than if he’d had to see them making out. And where Derek was private and quiet about their relationship, Stiles was loud and talked a lot about it.

And he’d been talking for weeks about how he was so excited about his and Derek’s second anniversary; he’d been sick with the flu during their first so they hadn’t been able to celebrate at all. He’d wagged his eyebrows as he told everyone to stay clear of Derek’s apartment that night, hinting at the no doubt carnal acts the two of them would be doing together.

And oh, how Isaac had wished he could be the one hinting at that. His plan had sparked into his mind months ago, but Stiles’ constant talking about their anniversary plans had really made him move forward with the idea. It had been difficult tracking down a witch who was willing to brew him a potion that wouldn’t cost him an arm and a leg, and then even more difficult to convince said witch to give him a dose of a memory twisting one, as well. And then he’d had to figure out how he would get away with it, and find a place to store his body during the time period – and a way to make it to that Stiles’, once he was in Isaac’s body, wouldn’t be able to escape and ruin everything.

Because, yea, Isaac’s plan was to switch places with Stiles, literally; the witch had given him a potion that would essentially swap their souls. There was a time limit; he’d be switched for just under twelve hours. That was just enough time for him to be able to enjoy the anniversary that he wished was his. He’d already secretly administered the memory potion on Stiles; it would kick in when they were back in their own bodies, making Stiles think the memories Isaac had created during the swap were his own, if a little muddled. Hopefully it would be enough that neither Derek or Stiles would ever know what he’d done.

He could give Stiles the lifetime with Derek that he was going to get; he just wanted one night with the werewolf, and then he’d promised himself he’d force his heart to move on and find someone else.

~~

He felt oddly tight in this new skin, but also stretched in a way. The witch had told him that it would feel weird to be in another person’s body for the first few minutes, and they were definitely right about that. In his actual body, he was taller and slimmer than Stiles was, so being shorter and broader suddenly make him feel off balance. Luckily he adjusted quickly, though; he’d once adjusted to going from human to werewolf, and this was easy in comparison. 

It was odd, though, realizing he couldn’t hear as well as he’d been able to just a few seconds ago. He’d forgotten what it was like, having the limited senses of a human. He’d been to Derek’s place thousands of times over the last few years, but now he had to actually look around himself to place where he was, whereas he’d normally know just by scent.

But he could still hear, and what he was hearing just then was the sound of glasses clinking in the kitchen. He got too hit feet, knowing who was in the kitchen, and while it was awkward to walk he got the hang of it before he made it to the doorway.

He leaned in, seeing Derek mixing something into a glass of water. In this body he finally felt safe enough to indulge, and he let his eyes travel over the broad shoulders of the werewolf’s back, lingering on the slightly tapered waist and his toned thighs. He’d had to stop himself from looking for so long, but now he didn’t need to. He could feel Stiles’ – no, his, for the night – body reacting to the view.

Derek, though he’d no doubt heard his approach, didn’t turn around until he was evidently done stirring, and when he did it was with a smile Isaac had never had directed at him before. He’d seen it plenty, though, in the two years that he and Stiles’ had started dating. It was a private smile reserved only for the human; it took his breath away.

“Hey, you,” Derek said quietly, turning to lean against the counter and taking up the glass. He raised it as a sort of nod, which Isaac didn’t understand fully, before taking a few long sips. “I’ll be ready in about half an hour; are you good to go?”

Isaac didn’t have any clue what he was talking about, but was able to deduce that they were most likely going out to eat. Derek would probably take Stiles to the diner rather than somewhere fancy; that man had no class. He glanced down at what Stiles had been wearing; it was just his regular wear, plaid shirt and hoodie and jeans. Definitely diner clothes. So he nodded, agreeing that he was most likely ready.

Derek smiled again, finishing off the glass before setting it down. He moved towards Isaac and cupped his cheeks, pecking him lightly on the lips. Isaac leaned into it, wanting more and dazed from the light contact alone, but the older man chuckled. “I’ve been looking forward to this for weeks; how did I get so lucky to have someone like you?”

He knew he should probably say something right then; Stiles talked so much it would be kind of suspicious, but the witch had warned him that sometimes the voices didn’t switch. He had been practicing imitating Stiles but he wasn’t sure he’d gotten it down all the way; it was the one kink in his plan, but he knew he still needed to do it. It was just one night.

So he shrugged and smirked, trying to shape his face in the way Stiles usually did, raising an eyebrow as if to say “who knows?” Derek raised an eyebrow in turn, and a somewhat evil look appeared on his face. “Oh, so we’re starting that already, are we? Do you want the gag now then?”

Which, okay, wow. Isaac definitely wasn’t expecting that. Well, sure, he’d assumed that Stiles at least was a kinky little shit, so it was natural to assume that their sex was less than vanilla, but Derek so casually bringing up something like gags meant that it was definitely more than a thing they did every once in a while. 

Also, if Derek was talking that way, did that mean they weren’t going out to eat? Then what had he meant by getting ready? 

But, still, this could actually be the thing that saved him. If he was gagged, he wouldn’t be able to slip out with his natural voice, even in the heat of passion. And, well, the idea of being gagged while Derek made love to him was hot. 

So he licked his hips, and nodded, trying to look as if he really wanted it. Honestly, though, his face was probably doing a good enough job of that on its own.

Derek grinned again, and it still had that slightly evil tilt to it, before he pushed Isaac lightly back towards the other room. They went up the stairs together, and Derek pulled him along into the bedroom. 

The werewolf grabbed something shiny off the bed, and held it out towards Isaac. It wasn’t a typical gag, which surprised Isaac; but then, he supposed to made sense that Derek wouldn’t want to completely silence Stiles. Stiles talked so much that no one would date him unless they actually liked how much he talked.

“You still sure about this?” Derek asked. “I know we’ve talked about it a lot, and I know it’s nothing we haven’t done before, but this is still different and I don’t want you to regret it.

As a way to avoid properly answering, Isaac gave into what he really wanted and pulled Derek into a deep kiss. They fell into it together, and Isaac wanted to cry that he was finally feeling it. It was better than he’d ever imagined it to be.

Derek pulled back way to soon, smiling again. “Okay, okay, I get it; you’re done talking about it. Open up, then.”

He was gentle as he inserted the ring gag into Isaac’s mouth; it was awkward for him, never having had one in before, but there was something… familiar about it that made Isaac think Stiles’ mouth had had it in plenty of times. The muscles didn’t feel overly stretched at all.

“You remember your safe words?” Derek asked as it was buckled on, and Isaac swallowed, opting for raising his eyebrows in what he hoped was an annoyed look. Stiles did that quite often. Derek rolled his eyes in turn. “Fine, I was just checking, you’re always on my case about doing these things properly.”

Isaac sighed in response.

“Well, just strip, then,” Derek said, rolling his eyes again.

He froze; yes, he’d known what was most likely going to happen tonight and been eager to have sex with who he felt was the love of his life, but so soon? He’d barely been in Stiles’ body for half an hour. Was that really all they had planned for their big anniversary, a night of sex?

Actually, why he’d ever thought Stiles would be involved in something more romantic than that he wasn’t sure; of course that’s what they had planned. And honestly, as much as he loved the guy, Derek didn’t seem the type to be comfortable with romantic gestures, so a night of sex probably suited him just fine as well.

As he was stripping, he finally took note of what else was laid out in the bed. And, well, it was a lot of rope mostly – in a funny turn of events, it looked like both him and Stiles were going to end up spending the night tied up.

That made his thoughts flick to the other boy, who would have woken up in Isaac’s body, tied up and alone and unable to see anything. He was probably freaking out, thinking he was kidnapped. He’d think Derek would notice he was missing on their anniversary and would be already on his way to rescue him, but he’d really just be left there alone while Isaac got to enjoy his anniversary in his place. That made him feel guilty, but he soothed the guilt by remembering that the memory potion would kick in when they were back in the right skins, and Stiles would be none the wiser to what had happened.

Derek didn’t wait once he was naked, just began arranging the ropes around his body, tying him up a lot more thoroughly than Isaac had tied up his own body earlier. He was lain on the floor as the ropes started climbing higher, stretched out flat with his legs tightly roped together, his arms spread flat along his sides. He could barely wiggle his fingers when Derek had tied the last knot; all he’d be capable of doing like this was an imitation of the worm.

And he still had the gag in, of course; his mouth was going slightly dry from the exposure to the air, but he could still feel himself getting hard at the feeling of being totally at Derek’s mercy.

“Ah, ah, ah,” Derek said mockingly when he noticed his reaction. “None of that tonight, remember?”

He slipped something around Isaac’s cock, something tight and restricting; it turned out to be a cock cage. A fucking cock cage. Man, these two were freaks. In any case, it prevented his cock from growing any harder; it was painful at the size he was at already, and he wasn’t into pain – too many traumatic memories for it to be a kink for him – so he quickly felt himself getting softer in reaction to it.

But his getting softer didn’t last long, because then Derek was stripping. He’d seen Derek naked before, after pack runs and after he’d completed his full shift, but that had only been for a few seconds and he hadn’t been able to look, then. But now, with the werewolf standing over his prone body, all he could do was stare at the muscles and tanned skin and dark hair that he was composed of.

And, of course, he found his eyes going directly to Derek’s dick. It was on its way to growing hard, as well, standing at about half-mast. Isaac hadn’t bothered to look much at Stiles’ cock so he had no comparison between the two, but he knew Derek was definitely packing more than Isaac was used to with his own set. It was mouth-watering to look at, really; the dry mouth he’d had a minute before was immediately in the past.

He’d expected Derek to rearrange him, maybe pick him up off the floor once they were clearly both ready to start and lay him on the comfortable bed, but that didn’t happen. Instead, the werewolf nonchalantly took a seat on his chest. Now Isaac was face to face with Derek’s cock, and oh, he was about to get fucked in the mouth. He’d dreamed about Derek doing that to him a lot, and whilst none of his fantasies had included the gag, he could get with it if it meant he got what he wanted. 

Evidently, despite how extreme the bondage was, Derek was going to take it slow. He slipped forward just enough to slip the head of his cock into Isaac’s mouth, but didn’t move farther than that. Wanting it desperately, Isaac did his best to reach out with his tongue, making contact with the tip of it and moaning at his first taste. It might have just been the salty taste of skin and sweat, but it was like biting into a giant piece of his favourite cake to him.

But his enjoyment was quickly stripped away as Derek’s dick twitched, and then his mouth was filling with a foul fluid. Isaac choked as it hit the back of his throat, and his eyes widened as he put together what was happening.

Derek was pissing in his mouth. And not just a little taste; full out going, using him like a urinal. Once again, like with the gag, Stiles’ body made him react on instinct and he began swallowing before his mouth overfilled. Tears stung his eyes slightly, but he fell back into a space he used to reserve for his dad’s beatings – a mindset where he could slip away from what was happening and move on instinct.

When he was finished, Derek actually fucking tapped himself off on the ring gag, shaking off the last few drops, before he stood back up to his full height. Rubbing his stomach, he sighed and began to leave the room. “It’s not going as fast as usual, so I’m going to leave for a little while, give it some more time to set in. Don’t move,” he said with a wink. He turned off the light before he went, leaving Isaac alone with his thoughts.

~~

It was maybe more than an hour when Derek returned, and Isaac had to sit there and deal with the terrible taste of piss coating his mouth – he’d barely been able to stop himself from crying and retching the whole time, but he was in too much of a shock at what had transpired to truly react to it.

Little did he know it was about to get so much worse for him.

Derek didn’t so much as walk into the room when he came back as he did hurry into it, and Isaac didn’t even blink before he had a face full of the werewolf. Derek sat down on his face this time instead of his chest, bringing his ass to his mouth instead of his cock. It was quite rough, and Isaac had enough sense to still be shocked that he would place his entire weight on Stiles’ more delicate human face, but there wasn’t much more time to follow that train of thought.

Because just like it had suddenly been filled with piss earlier, Isaac’s mouth was filled again. This time with a substance coming from Derek’s ass; this time, with shit.

Derek had pissed in his mouth like a urinal, and now he was shitting in it like an actual toilet. It was hot, and syrupy, and absolutely foul. Isaac retched as it first touched his tongue, but the seal Derek had made was too tight for it to go anywhere. Acid burned his nose as a bit of it was forced up through there, but he knew immediately what he was going to have to do.

He was going to have swallow it; he was already having trouble breathing, there was so much of it in his mouth. Resigned, he took the first gulp. He gagged it immediately back up, but there wasn’t time for that; Derek was still unloading more into his mouth, and soon it would be so full more than some stomach acid would be forced through his nose. So he brought himself back to the beating space, and began to empty his mouth down into his stomach.

The entire time he was swallowing, he could make out the words Derek was saying above him. “I love you so much, baby; oh god, Stiles, you’re perfect.” He’d wanted Derek to tell him he loved him a million times, but never like this.

When he was evidently finished, Derek stood up without looking at him, making his way to the bathroom. Isaac managed to make a sound before he was fully out of sight, and the older werewolf turned towards him quizzically. “What was that?”

Isaac made the sound again, desperate for Derek to untie him.

But Derek just smiled and shook his head. “You know what we talked about, baby; no talking unless it’s your safe word.” And then he was gone, leaving Isaac alone to his tears.

~~

Derek came in and out of the room for the next couple of hours, most of the time just to empty his bladder – he must have been drinking a lot in order to need to go so often – but sometimes to let out another torrent of runny shit. Isaac was resigned to it now; he’d tried a few more times to get the safeword, but Derek had ignored him every time, so he’d given up on that.

The only hope he had now was that time would pass quickly, and the potion would wear off and he’d be away from all of this.

At some point, Derek came in and pissed once more, but instead of leaving the room, he crawled into bed and fell asleep, leaving him on the ground as he sunk into dreamland. But Isaac couldn’t sleep, not with the taste in his mouth or the horrible thoughts of what had happened going through his mind.

Looks like in addition to both being tied up, Stiles and Isaac had both been tortured tonight, just in very different ways.

~~

By the time he felt the telltale tingling in his fingers again, he was more than ready for the night to end. When he returned to his own body and escape from the bondage, taking note of the healing marks over his arms and legs where Stiles had evidently injured his body trying to escape, he knew one thing for certain – he wasn’t going to have a hard time getting over his love for Derek. In fact, he was never going to be able to look at Derek the same way again.

Man, he wished he’d thought to get an extra dose of the memory potion from the witch, just in case. But he’d thought he’d want these memories for the rest of his life, and now, he was hoping he could find away to get rid of them as soon as possible.

A few days later, he overheard Scott asking Stiles how their anniversary had gone; he wanted to throw up as the boy had pasted on a (literal) shit-eating grin. “Scotty my man, you wouldn’t believe me if I told you.”

**Author's Note:**

> A different take on the usual "body swap" trope, but one I've been kicking around for months. Hopefully it's as good to you guys as it was to me when I had the idea. Also, I didn't officially tag it was "non-con" because _technically_ , Isaac wanted to switch places with Stiles and have Derek treat him the way he treats his boyfriend, he just... _really_ didn't know what he was getting into. But I added the "non-con/rape elements" tag just to be safe.


End file.
